[Feature flag] Clean up `vsa_predefined_date_ranges`
## Summary
This issue is to cleanup the `vsa_predefined_date_ranges` feature flag, after the feature flag has been enabled by default for an appropriate amount of time in production.
## Owners
* Team: ~"group::optimize"
* Most appropriate slack channel to reach out to: `#g_plan_optimize`
* Best individual to reach out to: @rcrespo3 @blabuschagne
* PM: @hsnir1
## Stakeholders
## Expectations
### What might happen if this goes wrong?
### Cleaning up the feature flag
- [ ] Specify in the issue description if this feature will be removed completely or will be productized as part of the Feature Flag cleanup
- [x] Create a merge request to remove `vsa_predefined_date_ranges` feature flag. Ask for review and merge it.
- [x] Remove all references to the feature flag from the codebase.
- [x] Remove the YAML definitions for the feature from the repository.
- [x] Create [a changelog entry](https://docs.gitlab.com/ee/development/feature_flags/#changelog).
- [x] Ensure that the cleanup MR has been deployed to both production and canary. If the merge request was deployed before [the code cutoff](https://about.gitlab.com/handbook/engineering/releases/#self-managed-releases-1), the feature can be officially announced in a release blog post.
- [x] `/chatops run auto_deploy status <merge-commit-of-cleanup-mr>`
- [ ] Close the feature issue to indicate the feature will be released in the current milestone.
- [x] If not already done, clean up the feature flag from all environments by running these chatops command in `#production` channel: `/chatops run feature delete <feature-flag-name> --dev --pre --staging --staging-ref --production`
- [ ] Close this rollout issue.
issue